If the night temperature drops by 50 degrees, the roadrunner's internal energy-conservation permits a lowering of body temperature to

If the night temperature drops by 50 degrees, the roadrunner's internal energy-conservation permits a lowering of body temperature to

• A. 101°F
• B. 98°F
• C. 94°F
• D. 90°F

Answer: (C)

Endotherms save energy by letting body temperature drop at night when it's cold. A roadrunner normally runs a bit above 100°F in its active state, but it can enter a mild nocturnal cooling to reduce metabolic demands during a chilly night. Dropping to about 94°F provides a meaningful energy savings while still keeping bodily functions safe and functional. A much smaller drop wouldn’t cut enough energy use, and dropping to around 90°F would be risky for the bird’s physiology. So 94°F is the level that balances energy conservation with safety, making it the best fit.

Endotherms save energy by letting body temperature drop at night when it's cold. A roadrunner normally runs a bit above 100°F in its active state, but it can enter a mild nocturnal cooling to reduce metabolic demands during a chilly night. Dropping to about 94°F provides a meaningful energy savings while still keeping bodily functions safe and functional. A much smaller drop wouldn’t cut enough energy use, and dropping to around 90°F would be risky for the bird’s physiology. So 94°F is the level that balances energy conservation with safety, making it the best fit.